Systems and methods for fracture mapping via frequency-changing integrated chips

Abstract

Systems and methods for fracture mapping may utilize frequency changing to aid in providing high-resolution mapping. Integrated chips may be injected into a well and dispersed into a formation. A downhole tool that provides a transmitter and receiver may be positioned in the well. The transmitter may transmit electromagnetic (EM) signals into the formation. The dispersed integrated chips may receive the transmitted EM signal and return a frequency-changed signal to the receiver of the downhole tool. Utilizing the returned frequency changed signal, the system is able to determine the locations of the integrated chips that have been dispersed into the formation and provide fracture mapping.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Patent Application Nos. 61 / 948,155, filed on Mar. 5, 2014, and U.S. Provisional Patent Application Nos. 61 / 979,187, filed on Apr. 14, 2014, which are fully incorporated herein by reference.FIELD OF THE INVENTION[0002]This invention relates to systems and methods for fracture mapping via frequency-changing integrated chips.BACKGROUND OF INVENTION[0003]In the past, many have proposed using nanoparticles as contrast agents to illuminate a reservoir or a hydraulic fracture. Some have proposed using nanoparticles to increase the conductivity of a reservoir. Others have proposed using magnetic nanoparticles to enhance magnetic permeability of the reservoir and change the velocity of electromagnetic waves propagated in the reservoir. Additionally, some have proposed using nanoparticles to change the electrical permittivity of the reservoir.[0004]All of the proposed methods discussed above change only the phas...

AI Technical Summary

Benefits of technology

The patent describes two types of methods for fracture mapping in a well. The first method uses integrated chips that are injected into the well and dispersed in the formation. These chips have a unique frequency that they change when they detect a magnetic field. The system uses a downhole tool to create a magnetic field and transmit signals into the formation. The chips then detect the magnetic field and send back signals that have a different frequency. By measuring these frequencies, the system can determine where the chips are located and create a map of the fractures. The second method uses time-domain methods, where the chips communicate with each other using directionally modulated signals. The distance between the chips can be determined by measuring the time difference between the signals. This process can be repeated with different chips to create a map of the fractures. The patent also mentions that these chips can be used to measure various properties of the reservoir, such as magnetic permeability or pH.

Problems solved by technology

This is a major factor that limits the effectiveness of these methods.

This significantly limits the sensitivity of the receiver, due to the interference caused by strong echoes reflected from the rest of the formation, boundaries of the horizontal-well, metallic objects (equipment) used in hydraulic fracturing, and / or the direct-coupling between the transmitter and receiver in the main transceiver.

As shown in FIG. 1a, the overlap between electromagnetic waves from direct coupling and reflected from the formation result in significant interference to the reflected signal, thereby making it difficult to accurately receive and detect the small fractures waves.

As a result, it is difficult to map the proppants for fracture mapping utilizing the abovenoted methods.

This problem is similar to the problem of clutter in radar.

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